Pavement breaker



Nov. 15, 1932. B. w. HORTQN PAVEMENT BREAKER 5 Sheets-Sheet l Filed June 29, 1931 Lili.

,Visa/A INVENTOR /l/lboron NO 15, 1932. B, W HORTON 1,887,762

PAVEMENT BREAKER Filed June 29. 1951 5 sheets-sheet 2 mmm/ 19 20 ml INVENTOR Belg; T/VIHorZOn PAVEMENT BREAKER Filed June 29, 1931 3 Sheets-Sheet 5 F'gll? iNvEN-roR Belg/1 WHofoU BY Qw. um

ATTORNEY f and gave out.

Patented Nov. 15, 1932 narran erases vIPATENT orme-E7 BENJAMIN W. HORTON, OF MODESTO, CALIFORNIA, ASSIGNOR TO ARCHIBALD M.

I MCNEIL, OF MODESTO, CALIFORN'IA.v Y

PAVEMENT BREAK-ER Application led .Tune 29,

This invention relates to portable or hand manipulated tools of the reciprocating hammer type such as are especially adapted for pavement breaking purposes; and particularly to one 'operated by an electric motor such as that shown in the patent of A. J. Carter, No. 1,566,733 dated December 22, 1925.

In theGarter structure the gearing between the driving motor and the rotary crank which was operatively connected to the hammer was arranged so that it was impossible to maintain this lgearing properly lubricated, and such gearing therefore quickly heated One object of the present invention is to mount such gearing so that it will always be immersed in a pan of lubricantes is necessary to insure quiet and efcient operation of the gears. I have also arranged the gearing so that it is symmetrically disposed relative to the transverse center of the tool, thusmore evenly distributing the weight and making it easier for the operator to manipulate the tool. Also the use of beveled gears and their objectionable features is avoided.

Another diicult feature in the Carter implement as I have had occasion to observe from actual use of the same lay in the mecha,- nism by which the hammer was reciprocated. This hammer was provided with an actuating' bar having a hook on its outer end for intermittent engagement by the crank pin. Due Vto the suddenness with which this' hook was thus engaged it tended to snap off, which of course disabled the tool. Another object of the present invention therefore-is to remedy this defect by providing a reciprocating mechanism for the hammer constructed so that this sudden shock and the corresponding strains are avoided and there is therefore no tendency to fracture any partn I have also mounted cushioning elements at various points so that the severe shocks and jars otherwise imparted to the Ametal as the hammer is released are absorbed to a large extent.

These objects I accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

1931. Serial No. 547,467.

In the drawings simil-ar'cha-racters of reference indicate corresponding parts in lthe several views Fia'. 1 is a rear elevation of the tool.

Fig. 2 is a side section of thesame taken on the line 2 2 of Fig. 1.

Fig. 3 is a front transverse section of the upper portion of the tool.

Fig L is a similar view of the Vlower portion of the tool.

Fig. 5 is a cross section taken on the` line 5 5 yof Fig. 4.

Referring now more particularly tothe characters of `reference on 'the drawings, the numeral 1 denotes a hollow rigid casing which is hereafter denoted as being the body of the tool. vSecured 'on top of and extending transversely 'of the Vbody is a horizontal bar 2 at the ends of which oppositely projecting handles 3 are mounted by means of which the tool is manipulated.V

Y Toward its lower end the body at the back vis formed with a `cylindrical housing 4 substantially the` same width as 'the body and in which an electric motor 5 is mounted. At one end the central portion of the motor housing is closed by a removable cover 6 which also extends partly over and is secured to an adjacent side wall of the body. vSaid 'cover therefore forms an enclosed chamber 7 with said side wall and with the end of the `motor housing.

A spur pinion 8 on the motor shaft is disposed in said chamber and is in mesh with vone of a train of spur reduction gears 9 in said chamber. One of said gears is mounted on a shaft 1Q which extends transversely of .and across the .body adjacent the lbackside of the same. Iheshaft terminates outwardly of the corresponding sidewall ofthe body and Vprojects into an enclosed chamber 11 formed by said side wall and a cover l12 welded thereon. A spur kpinion 13011 said end of the shaft 10 engages a gear 14, both said `pinionand gear being enclosed in the'chamber 11.

Thisgear is mounted on a transverse shaft i 15 which -is -journale'd in Land extends across socket under the head. The head is held in place by a cap 23 aboutthe stem and secured to the hammer so as to practically form a part thereof; said cap forming a bearing for the lower ond of the spring 19. The stem is therefore mounted in yieldable connection with the hammer. Said stem projects upwardly through the body and at its upper end is slidably guided in a sleeve 24 formed at the top of the body. Inside the body the stem is formed with an enlarged portion 25 which is provided with a verticle slot 26 to receive the cam and with another intersecting slot 27 in its sides to freely receive the shaft 15.

The hammer is adapted to engage a tool element which is in the form of a drill rod 28 slidably mounted in a sleeve 29 which is secured to and depends from the barrel. A

collar 30 on the rod between the ends of the sleeve limits its vertical `movement; a compression spring 31 between the collar and a stop below cushions the downward movement of the rod and tends to force the upper end of the same a certain distance into the barrel.

When in itsfuppermost position the upper end of said rod projects above a rubber cushion link 32 mounted in the lower end of the barrel and against which the hammer abuts when in its lowest position. The cam engages the stem portion 25 at the top of the slot 26, and is designed to impart two lifting movements to the stem and hammer with each rotation of the shaft 15. The cam surfaces are arranged to lift the stem sufficient to compress the spring 19 to a considerable extent, and to then suddenly let go or become disengaged from the stem so that the hammer will descend with considerable force. This descent of the hammer will impart a similar sudden movement to the tool rod, the cushion 32 being arranged so that when the hammer engages the same the camengaging surface of the member 25 will then be slidably clear of the lowest point of the cam.

With this downward blow of the hammer on the rod, assuming that the latter resists downward movement, the bar is cushioned by reason of the cushioning member 22 interposed between the hammer stem and the hammer. At the same time this cushion does not of` course interfere with the entire strength of the blow being delivered to the drill rod.

In operation the tool is held in an upright position by the handles 3, there being a switch box 33 for the motor circuit mounted in connection with the bar 2 adjacent one end. The switch is controlled by a grip 34 extending alongside the handle and arranged in connection with the switch structure to close the same when the grip is depressed against the handle.`

From the foregoing description it will be readily seenthat I have produced such a de-V vice as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

IIa-ving thus described my invention what I claim as new and useful and desire to secure by Letters Patent is:

1. In a pavement breaking implement having a spring urged reciprocating hammer, a rotary element, and means between the hammer and element to move the hammer in one f direction, a body in which the element is disposed, a shaft for the element journaled in and projecting from one side of the body, a motor housing formed with the body transversely thereof, a motor in the housing whose axis is parallel to the shaft, a pinion on the motor disposed outwardly of the side of the body opposite to that from which said shaft projects, a gear on the outer end of the shaft, and reduction gearingbetween-said pinion and gear `disposed outwardly of the body; said reduction gearing comprising a pinion meshing with the gear, a shaft on which said pinion is mounted disposed parallel to the laxis of the motor and extending across and journaled in the body to and beyond the same .side thereof as that on which the motor pinion is disposed, and gearing between the corresponding end of said pinion shaft and the motor pinion. j

2. A structure .as in claim 1, with covers over the reduction gearing on both sides of the body and removably secured thereto, said covers forming, with the adjacent walls of the body, lubricant retaining enclosures about il the gearing.

In testimony whereof I affix my signature.

BENJAMIN W. HORTON. 

